Manual steering rack problem

[LRT]

The manual steering rack on my 1977 Triumph 2500 TC has quickly developed over the last few weeks a resistance when turning that builds up and then quickly loosens as though it is winding up and suddenly releasing when driving at all speeds.

When driving quickly on a gravel road the sudden slack is enough to cause the rear of the car to step out - not particularly pleasant when driving at 80kph!

The right hand tie-rod end was worn so I replaced both and set the toe-in to the specifications in the workshop manual using two tape measures from the brake discs.

I then tried turning the steering from lock to lock whilst the cars front end was suspended off the ground and the same alternating resistance is occurring so it can't be an alignment problem. Although the toe-in was out a long way before I replaced the tie-rod ends.

Could this be wear in the steering rack pinion? The rack looks ok when viewed at full lock with the boot slid back and there isn't any visible play in the steering column uni-joints nor the inner ball joints.

I could take it in for a front wheel alignment just to check the toe-in but I'm reluctant to do so at this stage as the struts and bushes are due for replacement and the front tyres (on S rims) are wearing on the inside edges and causing steering shudder.

I suspect the tendency for the car to initially under steer on a gravel corner coming through the apex and then switching to an uncontrollable 180° oversteer is due to the suspension and the half shafts (or a little driver error 😉 ) but I never had this problem with the steering rack beforehand.

The car does regularly travel over potholed and corrugated gravel roads so I'm sure this has something to do with the decline in suspension performance!

[josh18]

Could the rack part have become slightly bent causing the varying resistance?

[LRT]

Good point - I hadn't thought of that.

It looks as though I'll have to pull it apart to see what's going on.

[LRT]

Here is a picture of the rack at full RH lock:

[Ridgetone Triumph]

Try disconnecting the tie rod ends from the hubs and try turning the rack again. Possibility that one of the suspension top mounts is seizing?

[poppyman]

Also possible seized ball joint I have had that before.

[thescrapman]

It is a faulty UJ I reckon, Had similar myself after I swapped  rack. Angles have changed slightly.

[Richard B]

Quoted from thescrapman

It is a faulty UJ I reckon,

I'm with Colin, sounds like a partially seized U/J in the upper or lower steering linkage.


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[RobPearce]

I also agree with Colin, having had exactly that on a Dolomite many years back. Also similar, but not the same, symptoms on the Toledo when one of the four bolts in the lower coupling fell out.

[Nick Jones]

Seriously doubt it's the rack.  Column UJ or strut-top swivels get my vote.  The UJ will often respond to penetrating oil.  This isn't a permanent cure, just proof of diagnosis!

Nick

[LRT]

Thanks for everyone's replies - much appreciated!

I disconnected the tie-rod ends from the hubs but there isn't any difference so it seems like a uni-joint.

I tried driving it while holding the steering wheel tight and I can feel it pull from side to side in the same way a conventional steering box will when worn. Maybe there's more than one problem?

The rack does move half an inch or so in the rubber mounts when the wheel is turned at standstill.

I'll try putting on some different tyres to see if there's any difference. Although that doesn't fix the steering wind up and release problem!

I do have a secondhand rack but I'm not sure if it's off a Mark I or Mark II. Is there any difference?

[thescrapman]

The rack has not been fitted if it moves that much.

There are sliding plates underneath to assist in tensioning the clamps

[Pete Lewis]

this does seem more column uj/flexibles than rack, but you must reduce the rack shift , re clamp or new rubbers etc.

Pete

[LRT]

I have ordered new SuperPro rack mounts and inner ball joint cup bushings as the current ones are probably the originals.

However, the rack has moved when turned at standstill ever since I bought the car in 2015 but this problem suddenly occurred and worsened very quickly. It's probably everything letting go!

Can the pinion be removed from the rack for inspection whilst the rack is still in the car?

I have applied penetration fluid to the uni-joints but there's no difference. I have a spare rack so I'll swap the uni-joints to see.

[Pete Lewis]

if the ujs are cross pins and cups you wont solve a seized cup needle roller with any oiling
certainly on many makes of  cars this lumpy wind up steering is always down to the column couplings seized .

Pete

[LRT]

I now have the new SuperPro bushes after they got lost in the post. https://superpro.com.au/find/s.....K/cid-999500921/vid-

What is the best way to realigne the steering rack when refitting it? I could mark the current position before I remove the rack but I'm also considering putting in a spare rack out of a wreck so the markings could be irrelevant.